The invention relates to a method and system for controlling a position of a laser spot of a laser beam irradiated by an optical pick-up head onto an optical storage medium, and more particularly, to a method and system for controlling a position of a laser spot of a laser beam irradiated by an optical pick-up head to be locked to a track center of an optical storage medium of a land and groove recording/reproduction type, such as a DVD-RAM disc.
Regarding a digital versatile disc (DVD) such as a DVD-Recordable (DVD-R) disc or a DVD-Rewritable (DVD+RW/DVD-RW) disc, accurately controlling a track offset of an optical pick-up head of a DVD drive during recoding data onto the optical disc is not of primary importance to the recording quality, that is because no obvious problem will occur even if the laser light spot emitted from the optical pick-up head is not locked to the center of a groove track (i.e. a data track) of the DVD-R/DVD+RW/DVD-RW disc.
However, regarding a DVD-RAM disc using groove tracks and land tracks for data storage, if the laser light spot emitted from the optical pick-up head is not locked to the center of a second track (e.g. the groove track) of the DVD-RAM disc while the DVD drive is recording data on the second track, data previously written on a first track (e.g. the land track) adjacent to the second track will probably be erased or overwritten, typically causing a large jitter value that represents poor recording quality. In the worst case, at least a portion of the data on the DVD-RAM disc becomes unreadable.